package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.index.FieldInfo.IndexOptions;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.util.IOUtils;

import java.io.Closeable;
import java.io.IOException;

final class FormatPostingsPositionsWriter extends FormatPostingsPositionsConsumer implements Closeable {

    final FormatPostingsDocsWriter parent;
    final IndexOutput out;

    boolean omitTermFreqAndPositions;
    boolean storePayloads;
    int lastPayloadLength = -1;

    FormatPostingsPositionsWriter(SegmentWriteState state, FormatPostingsDocsWriter parent) throws IOException {
        this.parent = parent;
        omitTermFreqAndPositions = parent.omitTermFreqAndPositions;
        if (parent.parent.parent.fieldInfos.hasProx()) {
            // At least one field does not omit TF, so create the
            // prox file
            out = parent.parent.parent.dir.createOutput(IndexFileNames.segmentFileName(parent.parent.parent.segment, IndexFileNames.PROX_EXTENSION));
            parent.skipListWriter.setProxOutput(out);
        } else
            // Every field omits TF so we will write no prox file
            out = null;
    }

    int lastPosition;

    /** Add a new position & payload */
    @Override
    void addPosition(int position, byte[] payload, int payloadOffset, int payloadLength) throws IOException {
        assert !omitTermFreqAndPositions : "omitTermFreqAndPositions is true";
        assert out != null;

        final int delta = position - lastPosition;
        lastPosition = position;

        if (storePayloads) {
            if (payloadLength != lastPayloadLength) {
                lastPayloadLength = payloadLength;
                out.writeVInt((delta << 1) | 1);
                out.writeVInt(payloadLength);
            } else
                out.writeVInt(delta << 1);
            if (payloadLength > 0)
                out.writeBytes(payload, payloadLength);
        } else
            out.writeVInt(delta);
    }

    void setField(FieldInfo fieldInfo) {
        omitTermFreqAndPositions = fieldInfo.indexOptions == IndexOptions.DOCS_ONLY;
        storePayloads = omitTermFreqAndPositions ? false : fieldInfo.storePayloads;
    }

    /** Called when we are done adding positions & payloads */
    @Override
    void finish() {
        lastPosition = 0;
        lastPayloadLength = -1;
    }

    public void close() throws IOException {
        IOUtils.close(out);
    }
}
